Antropogenic materials in the nests of Passerine birds in the west of Ukraine

Abstract

Background. Traditionally birds build their nests out of natural materials that are usually found near the location of the future nest. However, along with the expansion of human economic activity and the appearance of various types of antropogenic mate­rials (hereafter debris) that pollute environment, they appeared in bird nests. Although it is hard to predict with certainty what significance this behavior will have for birds in the future, it is possible to investigate which species are prone to such behavior, which unnatural materials birds choose to build nests, and which factors influence it. This makes it possible to predict how changes in the environment by humans affect the nest-building behavior of different species of birds and the species-specific appearance of the nest. Moreover, incorporation of debris into birds’ nests may be used as an indicator of environmental pollution. Materials and Methods. Materials for this article included 382 nests of 42 passerine species. Nests were collected unevenly during the last two decades in different stations across the western part of Ukraine. Among them, 18.3 % of the nests were located within the borders of human settlements, 48.2 % on their outskirts, and 37.5 % in the natural or close to the natural environment far beyond settlements. Nests were decomposed with laboratory forceps and nest components were identifined as natural (grass, plant stems, tree leaves, grass roots, moss, mammalian hair, bird feather and others) and antropogenic (threads, synthetic fibers, fluff, ropes, fishing line, cigarette butts, paper, tissue, wires and others), and their percentage by volume was defined. Results and Discussion. To construct nests, birds use antropogenic materials in the form of debris/solid waste, which they find in the surroundings. Among 382 analyzed passerine nests (42 species) collected in the west of Ukraine, artificial or man-changed materials were recorded in nest construction of 103 nests (27.0 %) of 26 species (61.9 %). Most frequently antropogenic materials are incorporated in the nests of the Fringillidae family (Linaria cannabina – 85.7 % of the analysed nests, Chloris chloris – 71.4 %, Fringilla coelebs – 66.7 %). The amount of artificial materials in the nest composition varied from minimal to up 100 %. More than a half (55.3 %) of the investigated passerine nests contain only a minimal or small amount of debris (≤ 1 % by volume). We found 17 types of anthropogenic materials in the nests. The most popular were threads (in 47.1 % of the analyzed nests with antropogenic materials), synthetic fibers (31.7 %), fluff (20.2 %, among them artificial fluff 14.4 %, cotton wool 4.8 %, fiberglass 1.0 %), plastic film (17.4 %), ropes (14.4 %), and fishing line (12.5 %). The number of various types of antropogenic materials in one nest varied from 1 (in 55.3 % nests), 2 (31.1 %), 3 (9.7 %), and 4 to 7 (3.9 %). The higher number of artificial material types in the structure of a bird’s nest may imply purposefulness of such beha­vior in the environment transformed by the human. Some selectivity of the types of solid waste (debris) that birds use for nest construction was noted. We assume that in most cases birds use antropogenic materials closely resembling the traditional natural ones usually used by birds of certain species. The new artificial components in the composition of the nest imply that nest buil­ding is not completely genetically programmed but there is a possibility to change it by adding something new – similar, or even different. It looks quite reasonable, as it facilitates adaptation in changed environments. Using antropogenic materials as nest components is still controversial. The species specific look of the nest has changed by a different degree in polluted environments. It is still questionable weather such behavior is beneficial for birds in the long-term perspective. We suppose that antropogenic components may have appeared as part of the nest in the environments with available solid waste. Intentional/unintentional substitution of some natural components for nest with antropogenic ones may occur because of their high resemblance. Sometimes debris is incorporated into the nest while suitable natural components are accessible. In a polluted environment the species specific appearance of a nest may change to a certain degree. Conclusion. Passerine birds use antropogenic materials (in the form of debris) for nest construction quite often. Debris was found in nests of 26 passerines species. Synantropic species used various types of artificial materials more often. 17 types of various anthropogenic materials were found in the nests. Some selectivity was noted. Birds use antropogenic materials that resemble natural materials, but occasionally choose completely different ones.